1995-1997 is the cut off date for electronics. It differed by OEM so there is no real specific date.
Personally I would stay away from any bus on a light duty cut-away chassis. At the most they had a 14,000 GVWR. The majority had a GVWR of about 12,000 lbs. By the time you subtract the weight of the bus and the people in it you don't have very much room to add creature comforts.
The are a lot of Type 'C' buses out there that are not full length. The IC BE bus was built specifically to fill the gap between the light duty Type 'A' and the full size Type 'C' bus. They had GVWR's of 19,500 to 24,000. And since they didn't weight significantly more than the light duty buses it gave them a whole lot more unused weight that could be used for creature comforts. With larger brakes and tires it means they actually went a lot more miles between replacement and repair.
Thomas and Blue Bird made buses very similar to the IC BE bus. Many times going back the 1990's they were built on IHC chassis and were mechanically identical to the IC bus. I would stay away from those that were built on the Ford or GM chassis as parts for them can be hard to find. Some of Thomas and Blue Bird buses were built on Freightliner chassis with the Cummins 5.9L engine and AT543 transmission.
The T444(E) is a great engine in the smaller buses. It was available with HP ratings as high as 230 HP. Engines that are rated at 190 can be pumped up very easily to a lot more with modifications available from Gale Banks Engineering. With the full size medium truck radiator and transmission cooler it is highly unlikely you will have problems with overheating.
Blue Bird made the TC1000 has a smaller version of the TC2000 and it too was built specifically to fill the gap bewteen the light duty Type 'A' and the full size Type 'D' bus. Like the IC BE it was built with GVWR's in the 19,500-23,000 range. Most had the Cummins 5.9L and AT543 power package.
The Thomas Saf-T-Liner FE MVP was also aimed at the same market. It had the Cummins 5.9L and AT543 power package.
Because the Thomas and Blue Bird really squeezed those power packages into the engine compartment they don't lend themselves to a lot of engine modifications due to lack of space.
I have seen some as short as five windows and most of the smaller ones had 6-9 windows.
Unless you decide to go with a gas powered Type 'A' I would go with a bus with the Cummins 5.9L or IHC T444 engine. Both are good for well over 250,000 trouble free miles. And while some people have issues with the AT540 transmissions, given reasonable care and understanding their limitations they will go just as far or farther than the engine.
When you get into the larger buses you have to decide if you want a Type 'C' with the engine out front with the service door behind the front axle or a Type 'D' with the service door in front of the front axle. The Type 'D' comes with the engine up front (FE), the engine in the middle, and with the engine out back (RE).
Each of the above buses have distinct advantages and disadvantages.
You will need to determine which one will work the best for you.
As far as power packages go, I would prefer an Allison MT643 which is found in the larger buses more often than not if they had bigger HP engines. My preferenes for power would be the DT466 or the Cummins 8.3L. I would tend to stay away from Mercedes-Benz and Cat. For your purposes any engine with a turbo is better than one without one.
In the pre-electronics buses the 12" window openings were optional in almost all of the buses. Even if you are height challenged having 78" ceilings are preferred to 75" ceilings. If you get old enough the inside height was as low as 72".
As far as who would have purchased some of these buses new, the small Type 'C' and Type 'D' buses would most likely have been purchased by urban/suburban schools. For the 40' rear engine buses with big HP, highway gearing, and pass through under the floor luggage compartments the buses would have been purchased as trip buses most likely by suburban/rural schools with regular trips that were long.
I hope this helps.
:Thanx: as usual, I am in awe of your vast knowledge and experiences here. 
